Dalriada or Dál Riata (as it was called in Ireland) was the kingdom of the Scots who migrated from County Antrim in Ulster to Argyll and eventually gave their name to Scotland. Aidan mac Gabhráin who reigned from 574 to 608 as king of Dál Riata built a strong navy and waged aggressive war raiding as far as the Isle of Man and the Orkney Islands. He was less successful in land battles and lost the Battle of Degsastan in 603 to the Angles. The kingdom's power in Ulster was greatly diminished by a decisive defeat by the O'Neill (Uí Néill) in 637 at the Battle of Mag Rath.
From then on the Dalriadans focused on their lands in Britain. Their rivals were the Picts to the north and the Angles of Bernicia to the east. On the south they were bordered by Strathclyde a British kingdom. Dunadd, in Argyll, was probably the seat of the kings of Dalriada. It has been excavated archeologically and in addition to fortifications many moulds for the manufacture of jewellery were found. A census of Dalriada exists, the Senchus fer n'Alba.
Dalriada was conquered militarily by the Picts but eventually overwhelmed them culturally. Kenneth MacAlpin, a Dalriadan, was first King of the united Picts and Scots reigning from 840 to 857, as the king of Alba or Scotland. The Viking raids of the 10th century broke the sea communication between Ireland and Scotland and contact was lost with the western lands of Dál Riata, but not before the Stone of Scone was brought over.